Process of extracting zinc from its ores.



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PROCESS 0F EXTRACUNG ZINC PGGM HS QMS.

APPLICAUON ma mAH. 22. 1912t x Y y 9256989@ 536k.

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rnvIN ANDREAS JoHANssoN, or TROLLHTTAN, SWEDEN, AssIGNon 'ro SOCIT ANONYME METALLURGXQUE PROCEDES DE LAVAL, OF BRUSSELS, BELGIUM.

PROCESS OF EXTRACTNG ZINC FROM ITS CRES,

i a-sesos.

Application led March 22, 1912.

To all whom may concern:

Be it known that I, IDVIN NonEAs .Io- Haxssox, a subject of the King of Sweden, residing at Trollhittan, in the Kingdom of lqivedcn, have invented certain new and useful Improvements in JProcesses of Extracting Zinc from Its Orcs, of which the following` is a specification.

It has hitherto heen proposed to extract zinc from zine ores or from zinc oxid in electric furnaces by introducing the charge in the form of a stack in the furnace, and subjecting the surface of the stack to the radiation from an electric are; fresh material heilig introduced from the back of the stack so that the material is pushed forward in accordance with the consumption. of its surface. It has been shown that the principal advantage of this method consists in 'he fact that the carbonaceous gases develoord in the comparatively cool parts'of the interior of the stack, are, in their escape, heated increasingly so that upon reaching the surface of the stack, they attain such a high temperature, that in the presence of excessive amounts of carbon they do not contain any carbon dioXid. In ordinary metallurgical 'processes this fact must be regarded as a great inconvenience rather than an advantage, since, when the gases escape from the furnace at a very high temperature, the thermal effect is diminished. Moreover as a certain proportion of the carbon dioxid is reduced to carbon monoXid a great amount of heat as Well as of carbon is consumed. In the special case mentioned however the process is necessary, as otherwise the' zinc vapors in the presence of carbon dioXid would oxidize according to the equation Zn-j-CO22ZnO-i-CO.

Even a very small amount .of CO2 causes a very low production of metallic zinc as it establishes an oxidation ofthe surfaces of the condensed zinc particles, thereby producing zinc dust or so-called poussiere According to the present invention it 1s possible vto augment the thermal eii'ect yvery considerably and to this end the process is carried out in an electric furnace, the charge Specification of Letters Patent.

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Serial No. 685,528.

outlet in this space; the charge adjacent to this open space being sufficiently hot and containing just-suiicient carbon to cause all the carbon dioxid formed in the charge to he reduced to carbon monoxi'd during the passage of the gas from the interior parts to the surface of the charge adjoii'iing the open space.

An important feature of the present invention is that the gases of reduction penej trate successively the hotter parts of the charge before escaping from the furnace.

In the accompanying drawing two einbodiments of a furnace, to which the present invention is applied, are illustrated in vertical section.

.in Figure l a shaft furnace is showmin the furnace chamber l of which the electrode :2 projects through the furnace top 3. The second yelectrode 4 is arranged in the furnace bottom. To the openings 5 and theI shafts 9 and 10 are connected, and through these openings the charge is introduced into the furnace-chamber l. In order Ito avoid the furnace being completely filled with the charge and to enable the gas outlet 13 being arranged in the neighborhood of the hottest partpf the furnace,- baille Walls 11, 12 depending from the top 3, are provided, which admit e. free space to be e.' :.ablishcd in the furnace in which the gas outlet 13 1s arranged. 'Ihewalls 11, l2 are arranged in such a manner that they inclose the hottest part ofthe charge surface and thus cause the formation of an open space at this point. Thus there is no surface of the charge adjoining this open space which is cool enough to permit gases escaping from such surface to contain carbon dioxid. rIhe carbon dioXid gases developed in the cooler parts of the charge, are thus compelled to move from the cooler parts to the hotter parts of the charge, so that they may be heated to a temifo Fig. 2 shows another construction of a furnace in which propelling screws are employed for introducing the charge. V

As in the previous example lindicates the furnace chamber, 2 the top electrode, and 4: the bottom electrode. Through one or more openings 14, 15 in the furnace Wall, the charge is continuously introduced by means of propelling screws or the like 16, 17,

Where'by, when the electrodes are placed in the center of the furnace, as shown, the Walls 11, 12 prevent the furnace from becoming completely filled With the charge. Also in this construction the carbon dioxid passes from the cooler parts-to the hotter parts of the furnace, Where it is reduced into carbon monoxld.

In vboth constructions the charge is introduced and the' gases escape in such a manner, that the gases are compelled to move in'the same direction as the charge and to pass through increasingly hotter parts of the charge, before escaping from the furnace.

What I claim and desire te secure by Letters Patent of the United States is The method of extracting zinc from its ores, which consists in introducing into an p electric resistance furnace a charge containing sufficient carbon to combine `with the oxygen of the ore to form carbon monoxid, passing an electric current through a portion of said ore to produce various degrees of heat in different parts of said ore, causing the carbon dioXid formed in the cooler parts of the charge to successively penetrate the hotter parts of the ore whereby the remaining unaltered carbon Will reduce it to carbon monoxid.

In testimony whereof I affix my signature in presence of two Witnesses.

EDVIN ANDREAS J OHANSSON. Witnesses:

VERNER SvAN'rEsoN, HUGO LLNDBORN. 

